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Electron beam and gamma ray irradiated polymerelectrolyte films: Dielectric properties
S. Raghu 1, K. Archana 1, C. Sharanappa 1, S. Ganesh 1, H. Devendrappa*,1
Department of Physics, Mangalore University, Mangalagangotri, 574199, India
a r t i c l e i n f o
Article history:
Received 16 February 2015
Received in revised form
28 May 2015
Accepted 24 October 2015
Available online 6 November 2015
Keywords:
Polymer electrolytes
FT-IR
Dielectric permittivity
Conductivity
Radiation effect
* Corresponding author. Tel.: þ91 824 228736E-mail address: [email protected] (H
Peer review under responsibility of The E1 Tel.: þ91 824 2287363; fax: þ91 824 22872
http://dx.doi.org/10.1016/j.jrras.2015.10.0071687-8507/Copyright© 2015, The Egyptian Socopen access article under the CC BY-NC-ND l
a b s t r a c t
In this study, polymer electrolyte films were irradiated with electron beam (EB) and Gamma
ray (GR) at 50 and 150 kGy. The induced chemical changes in films due to irradiations have
been confirmed from the Fourier Transform Infra red (FT-IR) spectra. The X-ray Diffrac-
tometry (XRD) results show that crystallinity decreases by ~20% in EB and ~10% in GR
irradiated films respectively compared to non-irradiated film. The micro structural
arrangement was investigated by Scanning Electronic Microscopy (SEM) and the images
reveal that there is a substantial improvement in the surface morphology in irradiated
films. The real (ε0) and imaginary (ε00) dielectric constant and AC conductivity are found to
increase with increase in irradiation dose. Improved dielectric properties and conductivity
(1.74 x 10�4 & 1.15 x 10�4 S/cm, respectively, for EB and GR irradiated films at room tem-
perature) after irradiation and it confirm that EB and GR irradiation can be simple and
effective route to obtaining highly conductive polymer electrolytes. From this study it is
confirm that EB is more effectiveness than GR irradiation.
Copyright © 2015, The Egyptian Society of Radiation Sciences and Applications. Production
and hosting by Elsevier B.V. This is an open access article under the CC BY-NC-ND license
(http://creativecommons.org/licenses/by-nc-nd/4.0/).
1. Introduction
In recent years, polymer electrolytes have been attracting
scientific and technological importance because of their po-
tential applications in many areas such as Li-ion polymer
solid state batteries, super capacitor, electro-chromic devices,
etc. Wright and Fenton first proposed the idea of preparation
of polymer electrolytes in 1973, but its technological signifi-
cances were achieved and appreciated by Armand et al. a few
years later Armand, Chabango, and Duclot (1998). As
advanced technology keeps on developing every day, the de-
mand for polymers is raising continuously, in particularly
3; fax: þ91 824 2287289.. Devendrappa).
gyptian Society of Radiat89.
iety of Radiation Sciencesicense (http://creativecom
polymer electrolyte because of its use in various promising
applications Khan and Qureshi (1999). PEO based polymer
electrolytes are still among the most extensively studied
polymer ionic conductors due to fast ion transport, and they
easily associate with other ions especially inorganic alkali and
transition salts Chiu, Chen, Kuo, Huang, and Chang (2004). In
particular to Cadmium chloride (CdCl2)-doped PEO has
attracted considerable attention because of fine tune their
fundamental physical properties by simply varying the cluster
size and composition makes them highly attractive for a va-
riety of possible applications Liu et al. (2001). The main
advantage of polymer electrolytes is the easy preparation of
ion Sciences and Applications.
andApplications. Production and hosting by Elsevier B.V. This is anmons.org/licenses/by-nc-nd/4.0/).
J o u r n a l o f R a d i a t i o n R e s e a r c h and A p p l i e d S c i e n c e s 9 ( 2 0 1 6 ) 1 1 7e1 2 4118
films of desired size and shape and its ability to form proper
electrode/electrolyte contact in electro-chemical devices.
These materials exhibit relatively complex multi-phase
behavior in crystalline as well as amorphous phase. In the
last few years, considerable efforts have been devoted to
develop the volume of amorphous in polymeric materials, for
which a number of different techniques such as doping,
blending, plasticization, and ionizing radiation were used to
reduce the crystallinity of polymer. In this case, EB and GR
radiation methods were used for modify the material phase.
Irradiation plays a prominent role in the modification of the
physical properties of polymers because the radiation process
directly provides the energy to the system. If ionizing radia-
tion is passed through the matter, the energy deposit in the
material causes irreversible changes in the macromolecular
structure of the target material. Hence, the application of ra-
diation in polymer technology has great importance to ach-
ieve desired modification in the physical properties polymeric
materials.
Therefore, modification of polymer has become an
important research area, mainly in industrial applications
such as wire and cable, electronic devices, medical, and ma-
rine Drobny (2002), Chmielewski, Haji-Saeid, and Ahmed
(2005) and Sperling (1992). On a large commercial scale,
various radiation processing techniques such as EB, GR, UV,
and X-rays or laser beams have demonstrated to be very
effective means of improving the end-use properties of
various polymers. In the present study, EB and GR irradiations
with various dosages were used to expose the polymer elec-
trolyte film, it interact with polymer chain could be undergo
crosslink or chain scission leading to alteration in the macro-
molecular structure, which is most effective because no spe-
cial additives are required. This structural modification in the
irradiated polymer electrolyte is directly influence on physical
properties; in this case the dielectric permittivity and elec-
trical conductivity were observed increased with increasing
the dose. The changes strongly depend on the physics and
chemistry of the absorbed materials; as well as the chosen
radiation energy and dose. The radiation effects may cause
occurrence of ionization or excitation of the electrons in
atoms, and displacement of atoms from their original site to
adjacent lattice sites of the solid permit charges should be
become free or loosely bonded to some trapping centers
elsewhere in thematerial structure as a result cross-linking or
chain scission Bouffard, Balanzat, Leroy, Busnel, and
Guevelou (1997) and Mujahid et al. (2004). The presence of
trapping charge within the material was influenced by the
induced radiation, thus of the increase in the transport
property Zahran, Kander, Hegazy, and Kassem (1993). Also, it
is observed that alteration in the functional group of polymer
causes a change in the physical properties of polymer films
Fink (2004) and Dworecki, Hasegawa, Sudlitz, and Wasik
(2001). In the past few years, the effects of EB and GR on
polymers have been investigated individually and some of the
results presented in the literature state that irradiation may
reduce crystallinity, induce cross-linking, and produce a un-
saturated carbonyl groups Cleland, Parks, and Cheng (2003),
Mishra et al. (2001), Perloni, Magistris, Chiodelli, Faucitano,
and Buttafava (1991), Nasef, Saidi, and Dahlan (2002) and
Shah et al. (2008).
Dielectric measurements are performed to know the in-
formation about the molecular dynamics and the charge
transportation mechanism in Polymer electrolytes films.
Polymers with high dielectric permittivity have received
increasing interest in recent years due to their potential ap-
plications in embedded capacitors, gate dielectrics and charge
storage applications as they provide advantage in size and
cost reduction. Literature survey reveals that, the dielectric
studies on ionically conducting solids although important and
valuable from scientific point of view, has not been studied
extensively due to the limitations and complexity in data
analysis.
Therefore, gaining a better understanding of the radiation
influence on the ion dynamics and segmental motion of
charges will facilitate to design new devices for required
purposes. In addition, it is important to understand how the
relaxation dynamics is affected by the dose. Thus, the effect of
radiation on the physical and structural properties of such
materials is required to be studied particularly, when such
devices are being used in the radiation environment. The
intention of this study is to investigate the effect of EB and GR
on the dielectric properties of polymer electrolyte films.
2. Experimental
2.1. Materials
The Polyethylene oxide (PEO, Mw ¼ 5� 106) powder was pro-
cured from M/s Sigma Aldrich Chemicals USA, Cadmium
Chloride (CdCl2) (M.W. 201.32) was obtained from SDFCL,
Mumbai, India, and methanol (acetone free) was obtained
from the NICE laboratory.
2.2. Methods
2.2.1. Polymer electrolyte film preparationThe filmwas prepared using the solution-cast technique. PEO:
CdCl2 (75:25%) was dissolved in methanol (CH3OH) and stirred
for approximately 6e8 hours at room temperature to obtain a
homogenous viscous mixture. The stirred mixture was cast
onto polypropylene dishes and allowed to evaporate at room
temperature. The thickness of the film was measured using a
Mitutoyo Dial thickness gauge and was determined to be
0.25 mm.
2.2.2. Irradiation sourceThe polymer electrolyte films were irradiated using electron
beam accelerator with 8 MeV-20A current, pulse repetition
rate of 50 Hz, pulse width 2.3 ms, and varying dose of 50, and
150 kGy in the air. They were also irradiated with gamma ray
(60Co source) at ambient temperature using a gamma cell at
fixed dose rate of 9.5 kGy/hour and varying doses of 50 and
150 kGy.
2.2.3. FT-IR studyThe FT-IR spectra of the non-irradiated and irradiated films
were recorded in the transmission mode using model AIM-
8800 FTIR Spectroscopy in the KBr medium. The spectrum of
the transmittance as a function of wave number in the range
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of 3500e500 cm�1 was recorded. The variation in trans-
mittance before and after irradiation was compared, and the
peaks were analyzed to study the chemical change.
2.2.4. XRD studyXRD patterns for non-irradiated and irradiated films were
recorded (Rigakuminiflex 600-bench top X-ray diffractometer)
at a scanning rate of 2�/min in the 2q range of 10e30� to study
the changes in the material phase.
2.2.5. Scanning electron microscopySEM images of non-irradiated and irradiated polymer elec-
trolyte films were obtained using the SEM (JEOL Model JSM,
390LV model).
2.2.6. Dielectric measurementsThe conductivity and dielectric parameters were measured
using PC-based Precision Impedance Analyzer (Model 6500B)
with PID temperature controlled having a frequency range of
40 Hz�1 MHz and temperature range of 303e323 K.
3. Results and discussion
3.1. FT-IR analysis
The FT-IR spectra of non-irradiated, EB and GR irradiated
polymer electrolyte films are shown in Fig. 1. It reveals that
some peaks intensity changed in the electron beam and
gamma ray irradiated films in comparison with non-
irradiated film. The bands at 940 and 1465 cm�1 is due to the
CH2 bending vibration, which correspond to the crystalline
phase seem to decrease with irradiation dose. This may be
attributed to the destruction of crystalline lamellar structure
of polymer. The intensity of the bands at 1654 and 1100 cm�1
respectively represents the ketonic carbonyl groups C¼C and
CeOeC group.
The change in intensity and transmittance of these peaks
indicates the occurrence of chain scission and cross-linking.
Fig. 1 e FT-IR spectra of (a) Non-irradiated, (b) Electron
Beam, and c) Gamma Ray irradiated films.
The peak at 2918 cm�1 is assigned the CeH stretching; the
increase in peak intensity in the irradiated films clearly in-
dicates that the CeH bond was affected because of the
breaking cleavage of H-bonds. This might be attributed to the
breakage of chemical bonds or formation/emission of low
molecular gases and radicals due to irradiation. The peak in-
tensity is increased and transmittance is decreased in EB
irradiated filmswith respect to that of gamma irradiated films.
Also, these results suggest that the affects are more pro-
nounced in electron beam compared to that of gamma ray
irradiation.
3.2. X-ray diffraction analysis
XRD analysis gives the effect of the radiation dose on the
structural phase of polymer electrolyte films. The X-ray
diffraction spectra of non-irradiated and irradiated films are
shown in Fig. 2. The XRD spectrum of a non-irradiated film
shows partly crystallinity and amorphous phase. The changes
in the structural parameters after irradiation affect the crys-
talline phase of the polymer; estimated values are cited in the
Table 1. The increase in FWHM (b) and peak intensity (I) is
clearly represent the decrease in crystallinity.
However, it is interesting to note that the crystallinity
decreased by ~20% in EB irradiated films and by ~10% in GR
irradiated films compared to non-irradiated film. These re-
sults suggest that EB irradiation is more effective than gamma
ray irradiation. Similar effects have been observed from
dielectric permittivity, AC conductivity, and FT-IR results.
Generally, the intensity and full-width half-maximum
(FWHM) are found to increase and the crystallite size
decrease. The average crystallite size (L) has been calculated
using the Scherer formula Cullity and Stock (2001). The vari-
ation of crystallite size, percentage of crystallinity, and
average inter-chain separation are shown in Table 1. After
irradiation, the average crystallite size, percentage of
Fig. 2 e X-ray spectra of a) Non-irradiated, b) EB, and c) GR
irradiated films.
Table 1 e Structural parameters for non-irradiated, EB and GR irradiated films.
Sample 2q d(A) b L (nm) R (nm) I Xc(%)
Non-irradiated 18.19 4.87 0.2817 28.19 31.28 126.1 47.2
EB (50 kGy) 18.60 4.76 0.2885 27.53 30.57 2308.2 27.3
GR (50 kGy) 18.99 4.67 0.4915 16.16 29.94 890.9 35.0
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crystallinity and average inter-chain separation are seen to
decrease for the prominent peak (first peak) due tomain chain
scission and cross-linking effect. These changes leads to dis-
order in the irradiated films thus enhance the amorphous
content in the irradiated films.
3.3. Surface morphology study
The SEM image analysis of the films provides the structural
information of their topographical and chemical composition.
The surface morphology of non-irradiated, EB and GR irradi-
ated polymer electrolyte films are shown in Fig. 3. It can be
seen that the surface of the non-irradiated film is smooth and
the spherulites structures are clearly visible as well as minor
surface cracks.
In irradiated films, it is clear seen that there is substantial
improvement in the morphology i.e., the surface gets rough,
increases in cracks depth and the spherulites structures
almost disappear as a result of which the amorphous region
would be dominant. The surface morphology seems to be
more uniform in EB than GR irradiated films and more
agglomeration is seen in GR irradiated films. It is seen that the
cross-linking effect is more in EB irradiation than GR irradia-
tion because of more electronic energy loss. These changes
clearly indicate displacement of the polymermolecules under
the impact of the incident irradiation. These obtained results
clearly suggest that the polymer get degraded due chain
scissoning and cross-linking. Hence, these improvements
favor to the ionic conductivity of films. These results well
correlated with the XRD and dielectric results.
3.4. Dielectric permittivity study
One of the important electrical properties for a material is its
dielectric permittivity (or relative permittivity, which is
generally referred to as the dielectric constant). For most
materials, the dielectric permittivity is independent of the
Fig. 3 e SEM images of Non-irradiated, EB an
electric field strength below a certain critical level, at or above
which the carrier injection into the material becomes
important.
The dielectric permittivity depends strongly on the fre-
quency of the applied alternating electric field or the rate of
the change of the time varying field. Fig. 4 shows the fre-
quency dependence of dielectric permittivity (ε0 & ε00) at
different temperatures for different irradiation dosage. The
dielectric permittivity is found to be increase with increasing
temperature and decrease monotonically with increasing
frequency perhaps due to the tendency of the induced dipoles
in themacromolecules to orient themselves in the direction of
the applied field in the lower frequency. However, at high
frequencies, the induced dipoles begin to lag behind in the
applied field or the alignment dipoles with the applied oscil-
lating field gradually failed as the frequency is increased and
hence, the dielectric permittivity maintain constant Reicha, El
Hiti, El Sonbati, and Diab (1991). This is a typical characteristic
of the disordered materials. The dielectric permittivity ε0
shows increase with temperature is emphasizing that when-
ever the temperature rises the dipoles orientation is facilitated
and relaxed producing increased dielectric permittivity
because of the decrease in the average structural time.
Also, it can be interpreted that the dielectric dispersion in ε0
is more pronounced at low frequency(1 kHz) as the tempera-
ture increases, which may be the total polarization in polar
dielectrics (dipolar, interfacial, and ionic polarization) Saqan
and Zihilif (2003), Fanggao, Saunders, and Lanbson (1996),
Prasad and Varma (2005). Similar results were observed by
Brosseau, Queffelec, and Talbot (2001), Kuo and Chang (2001),
Saravanan, Anantharaman, and Venkatachalam (2006). Fig. 4
(b, d & f) shows the temperature dependence of the dielec-
tric loss (ε00) with frequencies. The ε00 shows an increase with
the increasing temperature due to charges acquire more
strength as a result of which become more flexible, hence
dielectric loss increases with temperature. It can also be
interpreted that the rapid response of the polar dipoles
d GR irradiated polymer electrolyte films.
J o u rn a l o f R a d i a t i o n R e s e a r c h and A p p l i e d S c i e n c e s 9 ( 2 0 1 6 ) 1 1 7e1 2 4 121
subjected to an applied external field, i.e., increasing tem-
perature decreases in the dipole relaxation time. From the
figures, it is clear that ε0 and ε00 increase with increasing tem-
perature. This can be attributed to the temperature induced
relaxation of the rigid structure, which is responsible for an
increase in the dipole orientation.
The dielectric permittivity increases with the increase in
the irradiation dose as shown in Fig. 5 (a & b). The dielectric
behavior of the polymer is due to the presence of an appre-
ciable number of defects in the form of chain scission, cross-
linking, discontinuity, bending, breaking of bonds, etc. in the
molecular chains. Upon irradiation, the increasing defects
results in the formation of a greater number of dipoles in the
polymer matrix that governs its dielectric properties. From
Fig. 5, compare the influence of EB and GR irradiation on the
dielectric permittivity of polymer electrolyte films and it is
Fig. 4 e Variation of ε′ & ε00 with frequency at differe
clearly seen that EB effects is more pronounced than of GR
irradiation because radiation tolerance level for EB exposure
may be slightly higher than for GR exposure. Due to the higher
dose rates and shorter exposure times of high energy EB
irradiation, which have been shown to form high concentra-
tion of defects, free radicals, unsaturated bonds. Hence, fa-
vours the high dielectric permittivity than GR irradiation.
3.5. AC conductivity study
Fig. 6 shows the frequency dependent AC conductivity of non-
irradiated and irradiated polymer electrolyte films. The in-
crease in AC conductivity with frequency and temperature
reveals that there may be more and more free charges are
involved in the hopping process through the defective sites
along the macro polymer chains.
nt temperatures for EB and GR irradiated films.
Fig. 5 e Variation of ε′ & ε00 with irradiation dose for EB and GR irradiated films.
Fig. 6 e Frequency dependence conductivity of the non-irradiated and irradiated films at different temperatures.
J o u r n a l o f R a d i a t i o n R e s e a r c h and A p p l i e d S c i e n c e s 9 ( 2 0 1 6 ) 1 1 7e1 2 4122
In addition, it also emphasizes that the increase in AC
conductivity with increasing temperature is due to the
buildup of ordered polymeric chains or symmetry, which al-
lows the charge transport to be still more effective. This is one
of the common characteristics of disordered materials. These
results suggest that conductivity changes significantly with
the irradiation doses due to the occurrence of chain scissoning
in polymer, which leads to faster ionic transport through the
polymer matrix assisted by larger segmental motion of the
polymer backbone Kumar, Deka, and Banerjee (2010). The EB
Fig. 7 e Dose dependent ac conductivity of EB and GR
irradiated films at room temperature.
irradiated film shows high conductivity value compared to GR
irradiated films as shown in Fig. 7. The total conductivity s(u)
at a particular temperature can be expressed by the power law
thus,sðuÞ ¼ sdc þAuS (1)
Where, sdc is the dc conductivity and A is a constant depen-
dent on temperature. The value of ‘S’ at every observed tem-
perature is calculated from the slope of log (s) versus log (f)
plot (Fig. 6).
The frequency exponent ‘S’ value lies between 0 and 1.
Such a universal dynamic response is found in a variety of
disordered materials. It is observed that the frequency expo-
nent (S) parameter decreases with increasing temperature as
shown in Fig. 8.
This result was clearly represents that the AC conduction
mechanism follows the correlated barrier hopping (CBH)
model Elliott (1987). The AC conductivity found increases and
the ‘S’ value decreases with the irradiation dosage. The values
are cited in Table 2.
The temperature dependence of S, based on this model is
S ¼ 1� 6kT=WM � kTlnð1=utoÞ (2)
Where, WM is the effective barrier height at infinite intersite
separation, t0 is the characteristic relaxation time, and k is the
Boltzmann constant.
The values of WM are obtained by the best-fitted parame-
ters to Eq. (2) and are given in Table 2. As irradiation dosage
enhances the value of WM as well as conductivity were found
to increase after irradiation. This is because the irradiation is
Fig. 8 e Temperature dependence of frequency exponent‘s’ for non-irradiated and irradiated films.
Table 2 e AC conductivity and frequency exponent(S) values for EB and GR irradiated films at room temperature.
Dose (kGy) sac(S/cm) S WM(eV)
EB GR EB GR EB GR
0 8.626 � 10�6 8.626 � 10�6 0.177 0.177 0.191 0.191
50 8.087 � 10�5 5.791 � 10�5 0.170 0.136 0.211 0.202
150 1.749 � 10�4 1.150 � 10�4 0.108 0.083 0.574 0.313
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expected to convert the polymeric structure into a hydrogen
depleted carbon network. This carbon network is believed to
make the polymer more conductive Wang, Curry, Tavenner,
Dobson, and Giedd (2004).
4. Conclusions
We have investigated the EB and GR irradiation induced
modifications in polymer electrolyte films using FT-IR, XRD,
SEM, and impedance techniques. The results show the change
in the crystallinity and chemical structures polymers after the
irradiation by EB and GR radiation. The modification in the
irradiated films was confirmed from FT-IR that the chain
scissoning/branching occurs for both process, as the intensity
of the wave number 1100 cm�1 enhances with incremental
irradiation. Another remarkable peak observed at 1654 cm�1
corresponds to the presence of C¼C group. An increase in the
intensity of this peak suggests the occurrence cross-linking.
The loss in crystallinity is slightly more in EB than in GR
irradiation. In addition, the effects of EB and GR irradiation on
structural morphology was investigated by SEM, and the im-
ages reveal that after irradiation there is improvement in the
surfacemorphology of the films. Themain results of this work
are enhancement of the dielectric permittivity and AC con-
ductivity of the polymer electrolytes after EB and GR irradia-
tions. The dielectric behavior of the polymer arises due to the
presence of an appreciable number of defects in the form of
cross-linking, discontinuity, bending, breaking of bonds, etc.
in the molecular chains. Upon irradiation, the increase in
these defects results in the formation of a greater number of
dipoles in the polymer matrix that governs the dielectric
properties, and which leads to faster ionic transportation
through the polymer matrix assisted by a larger segmental
motion of the polymer backbone. The exponent ‘s’ decreases
with increasing temperature, which clearly suggests that the
AC conduction mechanism follows the correlated barrier
hopping (CBH) model. Irradiation processes promoted an in-
crease in the dielectric permittivity and conductivity value.
The overall result shows that the effects aremore pronounced
in electron beam compared to that of gamma ray irradiation
because of its more electronic energy loss in EB irradiation.
Acknowledgment:
The authors are thankful to the DAE-BRNS, Mumbai, India for
sanctioning the research project (No: 2010/24/34/BRNS dated
28 July 2010). Our thanks are also due to the personnel of
MICROTRON and CAART, Mangalore University, India for
providing the electron and gamma irradiation facilities,
respectively.
r e f e r e n c e s
Armand, M. B., Chabango, J. M., & Duclot, M. (1998). Secondinternational meeting on solid electrolytes, Standee's. Scotland:Extended Absts.
Bouffard, S., Balanzat, E., Leroy, C., Busnel, J. P., & Guevelou, G.(1997). Cross-links induced by swift heavy ion irradiation inpolystyrene. Nuclear Instruments and Methods in Physics ResearchSection B: Beam Interactions with Materials and Atoms, 131, 79e84.
Brosseau, C., Queffelec, P., & Talbot, P. (2001). Microwavecharacterisation of filled polymers. Journal of Applied Physics,89, 4532.
Chiu, C. Y., Chen, H. W., Kuo, S. W., Huang, C. F., & Chang, F. C.(2004). Macromolecules, 37, 8424-8430.
J o u r n a l o f R a d i a t i o n R e s e a r c h and A p p l i e d S c i e n c e s 9 ( 2 0 1 6 ) 1 1 7e1 2 4124
Chmielewski, A. G., Haji-Saeid, M., & Ahmed, S. (2005). Progress inradiation processing of polymers. Nuclear Instruments andMethods in Physics Research B, 236, 44e54.
Cleland, M. R., Parks, L. A., & Cheng, S. (2003). Applications forradiation processing of materials. Nuclear Instruments andMethods in Physics Research B, 208, 66e73.
Cullity, B. D., & Stock, S. R. (2001). Elements of X-ray diffraction (3rded.) New York.
Drobny, J. G. (2002). Radiation technology of polymers. NY: CRC Press.Dworecki, K., Hasegawa, T., Sudlitz, K., & Wasik, S. (2001).
Modification of electrical properties of polymer membranes byion implantation (II). Nuclear Instruments and Methods in PhysicsResearch Section B: Beam Interactions with Materials and Atoms,185, 61e65.
Elliott, S. R. (1987). AC conduction in amorphous-Chalcogenideand Pnictide semiconductors. Advances in Physics, 36, 135.
Fanggao, C., Saunders, G., & Lanbson, E. (1996). Temperature andfrequency dependencies of the complex dielectric constant ofpolyethylene oxide under hydrostatic pressure. Journal ofPolymer Science Part B: Polymer Physics, 24, 425.
Fink, D. (2004). Fundamentals of ion-irradiated polymers. Springer.Khan, H. A., & Qureshi, I. E. (1999). SSNTD applications in science
and technology e a brief review. Radiation Measurements, 31, 25.Kumar, A., Deka, M., & Banerjee, S. (2010). Enhanced ionic
conductivity in oxygen ion irradiated poly (vinylidene fluoride-hexafluoropropylene) based nanocomposite gel polymerelectrolytes. Solid State Ionics, 181, 609e615.
Kuo, D. H., & Chang, C. C. (2001). Dielectric behaviour of multi-doped BaTiO3 epoxy composites. Journal of the EuropeanCeramic Society, 21, 1171.
Liu, B., Xu, G. Q., Gan, L. M., Chew, C. H., Li, W. S., & Shen, Z. X.(2001). Journal of Applied Physics, 89, 1059.
Mishra, R., Tripathy, S. P., Dwivedi, K. K., Khathing, D. T.,Ghosh, S., Muller, M., et al. (2001). Range and energy-loss rateof 118 MeV 28Si in some polymers using PADC as detector.Radiation Measurements, 33, 845e850.
Mujahid, M., Singh, P., Srivastava, D. S., Gupta, S., Avasthi, D. K., &Kanjilal, D. (2004). Study of chain scission versus cross linking
in MeV ion-irradiated polycarbonate using dielectric constantmeasurements and UV spectroscopy. Radiation Measurements,38, 197e203.
Nasef, M. M., Saidi, H., & Dahlan, K. Z. M. (2002).Investigation of electron irradiation induced-changes inpoly (vinylidene fluoride) films. Polymer Degradation andStability, 75, 85e92.
Perloni, P., Magistris, A., Chiodelli, G., Faucitano, A., &Buttafava, A. (1991). Effects of gamma-radiation on polymerelectrolytes: PEO and PEO20-LiClO4. Radiation Physics andChemistry, 37, 615e621.
Prasad, N. S., & Varma, K. B. R. (2005). Evolution of ferroelectricLiNbO3 in a reactive glass matrix (LiBO2eNb2O5). Journal ofNon-Crystalline Solids, 351, 1455.
Reicha, F. M., El Hiti, M., El Sonbati, A. Z., & Diab, M. A. (1991).Conducting polymers. V. electrical conductivity of polymercomplexes of bis-2, 6- Diaminopyridine sulphoxide-copperhalides. Journal of Physics D: Applied Physics, 24, 369.
Saqan, S. A., & Zihilif, A. M. (2003). Temperature dependence ofthe electrical properties of PEO/salt complex composite.International Journal of Polymeric Materials, 52, 387.
Saravanan, S., Anantharaman, M. R., & Venkatachalam, S. (2006).Structural and electrical studies on tetrameric cobaltphthalocyanine and polyaniline composites. Materials Scienceand Engineering B, 135, 113e119.
Shah, S., Singh, N. L., Qureshi, A., Singh, D., Singh, K. P.,Shrinet, V., et al. (2008). Dielectric and structural modificationof proton beam irradiated polymer composite. NuclearInstruments and Methods in Physics Research B, 266, 1768e1774.
Sperling, L. (1992). Introduction to physical polymer science. NewYork: Wiley Interscience Ed.
Wang, Y. Q., Curry, M., Tavenner, E., Dobson, N., & Giedd, R. E.(2004). Ion beam modification and analysis of metal/polymerbi-layer thin films. Nuclear Instruments and Methods in PhysicsResearch B, 219, 798.
Zahran, A. R. R., Kander, A. Y., Hegazy, A. A., & Kassem, M. E.(1993). Ultrasonic and thermal properties of g-irradiated low-density polyethylene. Applied Polymer Science, 49, 1291.